| License Code | License Type |
|---|---|
| al | Aquaculture license |
| cfc | Commercial fishing crew |
| cfs | Commercial fishing single |
| cpc | Commercial pelagic and anadromous crew |
| cps | Commercial pelagic and anadromous single |
| cs | Commercial shellfish |
| csc | Commercial shrimp crew |
| cso | Commercial shellfish + 70 |
| css | Commercial shrimp single |
| csu | Commercial shellfish under 18 |
| e0 | Elver dip net |
| e0c | Elver dip net crew |
| e1 | Elver 1 fyke net |
| e1c | Elver 1 fyke net crew |
| e2 | Elver 2 fyke net |
| e2c | Elver 2 fyke net with crew |
| e6 | Elver dip net 1 fyke net |
| e6c | Elver dip net 1 fyke net crew |
| ep | Eel pot |
| fhc | Federal halibut crew |
| gc | Green crab |
| la | Lobster crab apprentice |
| lao | Lobster crab apprentice + 70 |
| lau | Lobster crab apprentace under 18 |
| lc1 | Lobster crab class i |
| lc2 | Lobster crab class ii |
| lc2o | Lobster crab class ii + 70 |
| lc3 | Lobster crab class iii |
| lc3o | Lobster crab class iii + 70 |
| lco | Lobster crab + 70 |
| lcs | Lobster crab student |
| lcu | Lobster crab under 18 |
| lnc | Lobster crab non commerical |
| md | Mussel dragger |
| menc | Menhaden commercial |
| menr | Menhaden non commercial |
| mh | Mussel hand |
| mwd | Marine worm digging |
| ncs | Scallop non commericial |
| nfhc | Non federal halibut crew |
| nfhs | Non federal halibut single |
| qm | Quahog (mahogany) |
| scd | Sea cucumber drag |
| sd | Scallop dragger |
| sdi | Scallop diver |
| sdt | Scallop with tender |
| spt | Spat |
| sub | Sea urchin dragger |
| suh | Sea urchin diver |
| sur | Sea urchin raking |
| surf | Surf clam boat |
| suwt | Sea urchin with tender |
| sw | Seaweed |
| sws | Seaweed supplemental |
| vh | Vibrio harvester |
License Networks
Harvester licenses in Maine
To focus on fishery access and harvester adaptability, we’ve removed indigenous licenses, non-residential, and post-harvest (i.e., processors, wholesalers, etc) from the data set.
Licenses Issued
Below are two plots depicting the total number of licenses issued per year and the number of unique license types issued per year
Time series of license holdings
Average license holdings
Below are the summary statisitcs of the average number of licenses held by an individual per year.
Call:
lm(formula = total ~ license_year, data = average_licenses)
Residuals:
Min 1Q Median 3Q Max
-1.4449 -0.4028 -0.2763 -0.1498 10.8396
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 22.4595495 0.2941945 76.34 <2e-16 ***
license_year -0.0105389 0.0001466 -71.89 <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Residual standard error: 0.8676 on 362770 degrees of freedom
Multiple R-squared: 0.01405, Adjusted R-squared: 0.01404
F-statistic: 5168 on 1 and 362770 DF, p-value: < 2.2e-16| r.squared | adj.r.squared | sigma | statistic | p.value | df | logLik | AIC | BIC | deviance | df.residual | nobs |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.01404631 | 0.01404359 | 0.8676377 | 5168.174 | 0 | 1 | -463243.4 | 926492.8 | 926525.2 | 273091.5 | 362770 | 362772 |
Annual License Network Metrics
Degree Centrality
“The degree of a node is the number of other nodes that single node is connected to.
Important nodes tend to have more connections to other nodes. Highly connected nodes are interpreted to have high degree centrality.”
Betweeness
“[Betweenness] ranks the nodes based on the flow of connections through the network. Importance is demonstrated through high frequency of connection with multiple other nodes. Nodes with high levels of betweenness tend to serve as a bridge for multiple sets of other important nodes.” Source
Annual Network Plots
Density time series and network plots are available here